uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Functional properties of low-modulus PMMA bone cements containing linoleic acid
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.ORCID iD: 0000-0003-4139-6913
(English)In: Article in journal (Other (popular science, discussion, etc.)) In press
Abstract [en]

Spinal augmentation using rigid acrylic bone cement may facilitate the formation of additional vertebral compression fractures (VCFs) in the vicinity of the collapsed vertebrae. It has been hypothesized that the use of less stiff bone cement could reduce the occurrence of adjacent VCFs. Acrylic bone cement modified with linoleic acid (LA) has been reported as a promising low-modulus alternative. However, several key properties remain unexplored. In this study, the flexural properties and screw augmentation capacity of the LA-modified cement were evaluated. The effect of sterilization through autoclaving was assessed in terms of LA composition and cement handling properties, glass transition temperature (Tg) and quasi-static compressive mechanical properties. 

The bending modulus, bending strength and pull-out force were, as with the compressive properties, significantly affected by the addition of LA, giving mechanical properties closer to those of vertebral trabecular bone. The maximum polymerization temperature was significantly lower for LA-modified cement (28.2 ± 0.4 °C for non-sterile and 31.1 ± 1.1 °C for sterile material) than the control cement (66.8 ± 3 °C). The setting time of the cements remained comparable, at between 20-25 minutes, but LA-modified cements could be injected over a longer period than the regular cement. Sterilized and non-sterilized LA-modified cements displayed similar injectability and mechanical properties over time. The Tgof sterilized LA-cement (78.0 ± 3.2 °C) was not statistically different from the Tgof non-sterilized LA-cement (74.7 ± 4.8 °C) but both were significantly lower than the Tgof the control cement (102.8 ± 1.3 °C). 

In summary, a sterilization process could be used without significantly affecting the functional properties of LA-modified cement. These cements displayed excellent handling and mechanical properties that more closely match those of osteoporotic vertebral bone. They exhibited a pullout strength comparable to some ceramic bone cements, demonstrating potential for use in applications where hardware needs to be applied. 

Keywords [en]
Acrylic bone cement, low-modulus, mechanical properties, bending, vertebroplasty, screw, pullout, sterilization
National Category
Materials Engineering
Research subject
Engineering Science with specialization in Materials Science
Identifiers
URN: urn:nbn:se:uu:diva-349057OAI: oai:DiVA.org:uu-349057DiVA, id: diva2:1199303
Available from: 2018-04-20 Created: 2018-04-20 Last updated: 2018-04-20
In thesis
1. Bone-compliant cements for vertebral augmentation
Open this publication in new window or tab >>Bone-compliant cements for vertebral augmentation
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Acrylic bone cement based on poly(methyl methacrylate) (PMMA) is commonly used during vertebral augmentation procedures for the treatment of osteoporosis-induced vertebral compression fractures. However, the high stiffness of the cement compared to that of the surrounding trabecular bone is presumed to facilitate the formation of new fractures shortly after surgery. The aim of the thesis was to develop and evaluate a PMMA-based bone cement that better matches the mechanical properties of vertebral trabecular bone. To fulfill this objective, different compounds were added to the initial formulation of bone cement to modify its functional properties. Linoleic acid (LA) was found to give the best combination of strength and stiffness without negative effects on the handling properties and its use was therefore further investigated. In particular, different application-specific mechanical properties of LA-modified cement as well as itsin vivoperformance in an ovine model were assessed. 

In summary, LA-modified cement exhibited bone-compliant mechanical properties immediately after incorporation of the additive, as well as adequate handling properties, in particular a lower polymerization temperature and appropriate setting time. The screw pullout strength from low-modulus cement was substantially reduced compared to regular PMMA cement, but comparable to some calcium phosphate based cements. The fatigue limit of LA-modified cement was considerably lower compared to regular PMMA bone cement when tested in physiological solution, but still higher than stresses measured in the spine during daily activities. The modified cement displayed similar inflammatory response in vivoto conventional cement, with no evidence of additional cytotoxicity due to the presence of LA. Finally, it was possible to sterilize the additive without significantly compromising its function in the PMMA cement.

The results from this thesis support further evaluation of the material towards the intended clinical application. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 92
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1676
Keywords
bone cement, low modulus, vertebroplasty
National Category
Materials Engineering
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-349028 (URN)978-91-513-0351-2 (ISBN)
Public defence
2018-06-07, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2018-05-16 Created: 2018-04-20 Last updated: 2018-05-16

Open Access in DiVA

No full text in DiVA

Authority records BETA

Robo, Céline

Search in DiVA

By author/editor
Robo, Céline
By organisation
Applied Materials Sciences
Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 20 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf